Garudapurana 1.237

The glorious Garuḍa Purāṇa [Chapter] 237. / The Blessed Lord said: / I shall declare the essence of the Gītā, spoken to Arjuna of old, / his mind yoked to the eight-limbed yoga, having traversed the whole of Vedānta.

Attainment of the Self is supreme, no other, the Self being devoid of body and the rest; / devoid of form and the rest, ending in the body, it is the eye because of being the inner organ.

The vital breath is devoid of consciousness, for it is perceived [as such] in deep sleep; / and 'I am not the Self' [is false], because of connection with worldly existence, sorrow, and the like.

Like a smokeless, blazing flame, luminous like the sun, / like lightning-fire in the sky, [the Self is] in the heart, by the self in the Self.

The ears and other [organs] do not each see themselves by themselves; / the omniscient, all-seeing Knower of the Field sees them.

When the Self shines forth like a lamp blazing on a canvas, / knowledge arises in men through the destruction of sinful karma.

Just as on the surface of a mirror, one sees the Self in the self; / [having enumerated] the senses and the sense-objects, and the five great elements,

the mind, the intellect, the ego, the unmanifest, and likewise the Puruṣa; / having thoroughly discerned the supreme, pervasive [reality], one becomes freed from the enemies of bondage.

Having entered the entire collection of senses with the mind, / and having established the mind in the ego, O son of Pāṇḍu,

and likewise the ego in the intellect, and the intellect in Prakṛti, / having placed Prakṛti in Puruṣa, one should fix Puruṣa in Brahman.

Having meditated, 'I am Brahman, the supreme light,' one is liberated. / This house has nine gates and five witnesses of the three [guṇas];

the wise person who knows it to be presided over by the Knower of the Field is an excellent sage. / Thousands of horse sacrifices and hundreds of Vājapeya sacrifices, / all together, are not worth a sixteenth part of the sacrifice of knowledge.

Thus in the glorious Garuḍa Purāṇa, in the first section called the first part, in the section on conduct, the two hundred thirty-seventh chapter, named 'Determination of the Essence of the Venerable Bhagavad Gītā.'